Greetings all,
I'm trying to decide which Hejnar rail to buy for focus stacking. I will be going up to 2-3x magnification max, so I don't think I'll need a rail with a micrometer. Would this rail be sufficient: http://www.hejnarphotostore.com/product-p/ms3_8.htm
Or do I need more precision/higher TPI? I've considering making my own using a used Newport or Velmex linear stage, but for my purposes I think that might be a bit much, and after purchasing all the parts it would still be around the same or more than a Hejnar rail.

David,
Don't know what optics and equipment you are using, but with an APS-C camera at 3x you will want to be able to move in increments of a about 50 microns. The rail you reference moves 1060 microns per turn. So you need to turn about 1/20 turn between steps at the high end of your range (18 degrees)._________________http://www.krebsmicro.com

A couple of inches travel would be enough, though it can be hard to get the camera in the right place to within that range, then more is useful.
Hejnar do make a 2", 100TPI rail, but for 3x that's finer than you have to have.
It might look tatty to tape a circular card with degree markings onto the knob of a nicely engineered rail, but it works. 100th of a turn becomes quite easy if the scale has a datum to work against.
My first stacks at 10x were done using the focus rail on a bellows, which is about 40mm per turn. I wouldn't say it was easy, but it worked.

As far as the subjects are concerned, if they're more than something like 2" deep you're usually better off turning the focus ring on the lens than using a rail.

Have you looked at a Velbon Mag Slider? Cheaper, etc..._________________Chris R

I have looked at the Velbon, it is definitely less expensive, though I have read some not so great reviews. I don't mind paying more for a better product that will last, which is why I'm leaning towards a Hejnar. I've seen your Velmex set up, which is wonderful, but maybe too much for my needs? My work will be with flowers, small plants and plant organs.

Hejnar, Newport, Velmex—all good brands. I agree with you on avoiding the Velbon, which is a significant step down from any of these. (I have more products than I can count from the three brands you named, and one Velbon Mag Slider.)

The particular Hejnar rail you referenced seems fairly well-matched to your purpose, if you’re comfortable with the 18 degree partial turns Charlie described. You might want to swap one of the turning knobs for one of a larger diameter, which would make this easier. The knob on this rail is a bit bigger and is flat, which is useful. You might ask Chris Hejnar if it would fit on your rail—he will customize things and is a good fellow to deal with.

The nice thing about a flat knob is that you can easily attach a circular card to it, as ChrisR described.

On the model you’re looking at, I particularly like the inclusion of a slider release button for rapid positioning, which you’ll find a great convenience. Velmex also has this available in their “Rapid Advance” feature. However, if you ever plan on working with this slide in a vertical orientation, you want to be very careful about that release button. Another nice thing about this slider is the fact that the bottom of the slider is already machined as an Arca dovetail. With a Velmex slide, you'd have to add this, which is not difficult.

Davids wrote:

One of my concerns with the more precise Hejnar rails is that the travel distance is so limited that it might be too short for 1:1 macro work.

I think a bigger issue with the finer-threaded Hejnar rails (up to 100 tpi) would be the tedium of turning the knob many times for simple adjustments and for return to the starting position. The slide release button would be really nice with these models, but doesn’t seem to be there. Also, for convenience of camera placement, you’d probably want to mount a rail with so little travel on something with more travel, such as a longer Hejnar rail. I showed such an approach here.

All this said, you’re considering a $300 manual rail, and $550 gets you into a fully automated StackShot. Automation is an enormous convenience. (My personal move to automation came after doing a 450-shot stack at 4x, then deciding to change to more oblique light and do it again, then deciding to add cross-polarization and do it again. That was enough tedium to prod me into dusting off the stepping motor I'd been meaning to integrate.) Automation is also more future-proof, as there is a good chance that after you get used to 2-3x, you'll want 5x, then 10x, and so on. As you go up in magnification, the number of shots in your stacks will also go up. From what I understand, a StackShot rail will handle 10x with ease, and higher magnification effectively, but with perhaps less ease. (Here I can't speak from experience, as I use the StackShot controller on my own hardware.)

I've definitely had my eye on the Stackshot system but I don't think I'm quite there yet. I plan on doing a large amount of macro work in the field. I like the relative simplicity of a manual rail like the Hejnar. Using Stackshot in the field looks like too much "stuff" to move around and set up. One of the main reasons I bought the Fuji Xt1 is the portability/small size of the camera. Adding more and more equipment kind of goes against that ideology. That being said, for all I know in about a year or so I'll have bought a larger sensor camera, stackshot, larger lighting, and so forth after getting hooked into the macro world!

I'll contact Chris Hejnar about the feasibility of switching out knobs.

I plan on doing a large amount of macro work in the field. I like the relative simplicity of a manual rail like the Hejnar. Using Stackshot in the field looks like too much "stuff" to move around and set up. One of the main reasons I bought the Fuji Xt1 is the portability/small size of the camera. Adding more and more equipment kind of goes against that ideology.

Ah, now I understand what you're looking to do. Agreed that the system you're building--camera, lens, and rail--seems like an efficient, minimalist solution for the field. I can imagine it being very satisfying to use, which is important.

It would be interesting to hear what you've planned for lighting. For 1x-3x plant work in the field, one of my favorite approaches is to use a white, translucent container of the sort in which deli-counters in grocery stores sell foodstuffs. (They'll typically give you these, or sell them for chump change.) You cut a hole in the tub to shoot through, and mount a couple of flash units sufficiently far from the tub to cast broad illumination upon it, and mount a powerful LED flashlight shining through a hole in the tub to provide light for focusing.

Quote:

That being said, for all I know in about a year or so I'll have bought a larger sensor camera, stackshot, larger lighting, and so forth after getting hooked into the macro world!

No need, in my opinion, to move to a larger sensor for macro work. Your camera's APS-C sensor is at a sweet spot for high-magnification macro work, as its size is very well-matched to the high-quality image circle of microscope objectives, which will be the optics of choice if you move to higher magnification.

I use both APS-C and full-frame 35mm DSLR bodies. For landscapes, portraiture, night-skies, event photography, and close-up work down to 1x, I usually choose full frame. But for macro work at magnifications above 1x (and small subjects shot with the 600mm telephoto, where the APS-C crop factor makes the lens act like a 900mm telephoto), I usually choose APS-C. For your plant subjects, APS-C should be all you ever need.

Also, if the time comes that you wish to automate, the Hejnar rail you've selected looks like something that could be easily adapted for automation. Just get a stepping motor compatible with the StackShot controller (the good folks at Cognisys are very helpful about this sort of thing, or you can ask me), a motor mount, a shaft coupler, a StackShot controller, and do a bit of DIY work. Presto, your Hejnar rail would be automated. I can easily envision an implementation where you could quickly clip the Hejnar rail into and out of such a rig, so that you could use it both for minimalist manual field work and automated work.

- If you have one Arca-type rail left to right, and another fore and aft, that'll give you some extended, coarse adjustments. There's a wide choice of plates and rails you can put between tripod and Hejnar, or Hejnar and camera. They're extra stuff to carry about, but an 8 inch rail can be a nuisance too.

- With a simple wooden clothes peg, or plastic sprung clamp on the focus knob as a crank, it's surprising how quickly you can travel a fine rail. An inch only takes a few seconds.

- Stackshot in the field, is not something I find very appealing. You have to sit and watch it anyway, you're unlikely to be able to go off for coffee. You'll probably have dozens rather than hundreds of shots in your stacks, with intervals only long enough for things to settle or flash to recycle, so a small number of minutes usually._________________Chris R